KR100311849B1 - Room temperature curing organopolysiloxane composition - Google Patents

Abstract

The present invention is an organosilicon compound (B) containing 0.1 to 100 parts by weight of an organopolysiloxane (A) terminated with a silane group or an alkoxy group, and an average of at least two hydrolyzable groups bound to silicon atoms (B) from 0.1 to It relates to a room temperature-curable organopolysiloxane composition comprising 30 parts by weight, 0.5 to 50 parts by weight of a hydroxyl-containing organic compound (C) capable of swelling a polyolefin resin, and optionally a necessary amount of a curing catalyst (D). . The compositions exhibit satisfactory adhesion to untreated polyolefin resins to provide sufficient adhesive strength to withstand long use in practical use.

Description

Room Temperature Curable Organopolysiloxane Composition

1 is a perspective view of a sample used in the Examples for shear adhesion test.

FIELD OF THE INVENTION The present invention relates to room temperature-curable organo pulleysiloxane compositions, and in particular, the present invention exhibits satisfactory adhesion to polyolefin resins (such as polypropylene or polyethylene) that are difficult to adhere to, and thus room temperature-curable adhesives useful as sealing compounds for polyolefin resins. It relates to a composition.

Polyolefin resins (such as polypropylene and polyethylene), which are nonpolar resins, have excellent heat resistance and molding properties as well as rigidity, although they are lightweight. Accordingly, these resins are molded by various molding methods to provide moldings which are widely useful as automobile parts, electrical equipment, building materials, furniture and daily necessities.

However, since polyolefin resins are non-polar, it is very difficult to adhere to other materials for fixing them, and it is difficult to endure in practical use when fixing with conventional adhesives.

In order to improve the adhesion of the polyolefin resin to such an adhesive resin, the polyolefin resin has been surface treated, for example, flame treated, corona discharged, treated with a chromic acid mixture, or an organic titanium compound or an organic aluminum compound. Or a primer treatment with chlorinated polyolefin.

However, such a surface treatment requires a treatment apparatus for this, and it becomes difficult to provide a uniform treatment when it is complicatedly formed or applied to a large product, and also involves an unwieldy operation process. The primer treatment method requires an apparatus for this depending on the primer coating method that is often used. Whichever device is chosen, the treatment process involves an additional step, which further complicates the bonding process.

On the other hand, room temperature-curable organopolysiloxane compositions are widely used as adhesives or sealing compounds in various fields in view of their good adhesion and the mechanical properties of cured products, but they hardly adhere to polypropylene or polyethylene.

In order to overcome the above-mentioned technical problems, the method of adhering between polypropylene resin and room temperature curable silicone rubber composition is disclosed in JP-A-60-135437 (wherein the term "JP-A" is disclosed unexamined). Means the Japanese patent application. This technique relates to a primer coating that provides a primer layer between adhesives, but still has the problem of complicating the adhesive treatment (process).

It is an object of the present invention to provide satisfactory adhesion to polyolefin resins (e.g. polypropylene or polyethylene) without requiring any pretreatment (e.g., primer processing) to provide sufficient adhesive strength to withstand practical use. It is to provide a room temperature-curable organopolysiloxane adhesive composition provided.

As a result of extensive research, the inventors have added a hydroxyl-containing organic compound capable of swelling a polyolefin resin to a room temperature curable organopolysiloxane composition in a condensation-curable form, thereby providing a composition having satisfactory adhesion to an untreated polyolefin resin. It has been found that this can be done and the above mentioned purpose has been described. The present invention has been completed based on this finding.

The present invention

(A) 100 parts by weight of organopolysiloxane terminated with a silanol group or an alkoxy group,

(B) 0.1 to 30 parts by weight of an organosilicon compound containing an average of at least two hydrolyzable groups bonded to silicon atoms per molecule,

(C) 0.5 to 50 parts by weight of a hydroxyl-containing organic compound capable of swelling a polyolefin resin, and optionally

(D) It relates to a room temperature curable organopolysiloxane composition containing an essential amount of a curing catalyst.

In FIG. 1 of this figure, numerals 1 and 2 are adhesives of the same material and 3 is an organopolysiloxane composition.

Component (A) is an organopolysiloxane terminated with silanol groups or alkoxy groups, which are generally used in room temperature curable organopolysiloxane compositions of the condensation cure type. Organopolysiloxanes having a viscosity of 100 to 500,000 cSt at 25 ° C. are preferred in order to impart adequate extrudability before curing and to provide a cured rubbery product with good mechanical properties. If the viscosity is less than 100 cSt, the resulting rubbery product tends to have insufficient mechanical properties. When the viscosity exceeds 500,000 cSt, the extrudability of the composition is deteriorated, and even when the inorganic filler is blended in order to obtain satisfactory mechanical properties, it is difficult to obtain a uniform composition. A particularly preferred viscosity range is 2,000 to 100,000 cSt.

Component (A) contains organic groups bonded directly to silicon atoms.

Component (A) is an organic group directly bonded to a silicon atom including alkyl groups (e.g. methyl group, ethyl group, propyl group, butyl group and hexyl group), alkenyl groups (e.g. vinyl group and allyl group), aryl Groups (e.g. phenyl groups), aralkyl groups (e.g. 2-phenylethyl groups and 2-phenylpropyl groups) and monosubstituted hydrocarbon groups (e.g. chloromethyl groups, β -cyanoethyl groups and 3,3 , 3-trifluoropropyl group). In terms of ease of synthesis, methyl groups, vinyl groups and phenyl groups are generally advantageous. Other groups of the organic groups exemplified above are only recommended if certain properties (eg cold resistance, heat resistance, oil resistance, etc.) should be imparted to the cured rubbery product. It is preferred that at least 85 mol% of all organic groups are methyl groups. In this case, the intermediates for component (A) are most readily prepared, the viscosity of component (A) being the lowest viscosity for the degree of polymerization of siloxane, and there is a good balance between the pre-cure extruded and the physical properties of the cured rubbery product. . More preferably, almost all organic groups are methyl groups. However, when the cured rubbery product must have cold or heat resistance, a phenyl group is used as part of the organic group, and when oil resistance is required, a 3,3,3, -trifluoropropyl group is used as part of the organic group. It is recommended to use.

Terminal silanol groups or alkoxy groups contribute to the curing reaction through reaction with the hydrolysis product of component (B). Examples of alkoxy groups are methoxy groups, ethoxy groups and isopropoxy groups. Among these terminal groups, silanol groups or methoxy groups are preferred in view of their reactivity.

Component (B) is an organosilicon compound containing on average two or more hydrolyzable groups bonded to silicon atoms per molecule. Component (B) is hydrolyzed by moisture and is immediately used to proceed with condensation reaction of silanol groups or alkoxy groups of component (A). Hydrolyzable groups include alkoxy groups (e.g. methoxy groups, ethoxy groups, propoxy groups, isopropoxy groups and butoxy groups), enoxy groups (e.g. propenoxy groups), isocyanato groups , Oxime groups (e.g. acetone oxime groups and butanone oxime groups), organoamino groups (e.g. dimethylamino groups, diethylamino groups, cyclohexylamino groups and isopropylanino groups) and amide groups (e.g. N -Methylacetamide group). Halogen atoms (e.g. chlorine atoms) or acyloxy groups (e.g. acetoxy groups and benzoxy groups) may in some cases act as hydrolyzable groups, but these groups generate hydrogen halides or acids upon hydrolysis to corrode It is generally undesirable because it causes overstimulation.

In addition to the hydrolyzable groups described above, component (B) contains a substituted or unsubstituted hydrocarbon group bonded to its silicon atom, similar to an organic group directly bonded to the silicon atom of component (A). In view of ease of synthesis and crosslinking rate, alkyl groups having 1 to 8 carbon atoms, alkenyl groups having 2 to 5 carbon atoms and phenyl groups are preferred as organic groups.

Specific examples of component (B) include alkoxysilanes and partial hydrolytic condensation products thereof (e.g. methyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane, ethyl orthosilicate and propyl ortho) Silicates); Enoxysilanes and partial hydrolysis condensation products thereof (eg, methyl triisopropenoxysilane); Isocyanatosilanes and partial hydrolytic condensation products thereof (eg, tetraisocyanatosilanes and methyltriisocyanatosilanes); Oxime silanes and their partial hydrolysis condensation products such as methyltris (acetone oxime) silane, methyltris (butanone oxime) silane and vinyltris (butanone oxime) silane; Aminosilanes and partial hydrolytic condensation products thereof such as methyltris (dimethylamino) silane, methyltris (diethylamino) silane, methyltris (isopropylamino) silane and methyltris (cyclohexylamino) silane]; And amidosilanes and partial hydrolytic condensation products thereof, such as methyltris (N-methylacetamido) silane.

The amount of component (B) used is usually in the range of 0.1 to 30 parts by weight, preferably 0.5 to 15 parts by weight per 100 parts by weight of component (A), but the amount of the silanol or alkoxy group of component (A) It may vary depending on the desired properties of the rubbery product. If the ratio of component (B) is less than 0.1 weight part, crosslinking will not fully advance. If it exceeds 30 parts by weight, the physical properties of the cured product are degraded.

The hydroxyl-containing organic compound as component (C) is a characteristic component that contributed to the development of adhesion to the polyolefin resin. Component (C) must essentially contain hydroxyl groups in its molecule and must be able to swell the polyolefin resin.

Component (C) includes aliphatic alcohols, substituted aliphatic alcohols, polyhydric alcohols, phenols and oximes. Other hydroxyl containing organic compounds such as escher alcohols, fatty acids and ketone alcohols do not meet the object of the present invention.

Among the hydroxyl-containing organic compounds mentioned above, aliphatic alcohols having cyclic, straight or branched hydrocarbon groups having 4 to 16 carbon atoms; Aliphatic alcohols having 2 to 8 carbon atoms substituted by aromatic hydrocarbon groups, halogen atoms or benzylamino groups; Aliphatic diols having 6 to 18 carbon atoms; phenol; And oximes having at least one of an aromatic hydrocarbon group and a cyclic, straight or branched chain aliphatic hydrocarbon group having 2 to 8 carbon atoms.

Aliphatic alcohols having 4 to 16 cyclic or straight chain hydrocarbon groups aliphatic alcohols having 2 to 8 carbon atoms substituted by halogen atoms or benzylamino groups; And oximes having at least one of an aromatic hydrocarbon group and a cyclic or straight-chain aliphatic hydrocarbon group having 2 to 8 carbon atoms.

Aliphatic alcohols having cyclic, hydrocarbon groups having 4 to 16 carbon atoms; Aliphatic alcohols having 2 to 8 carbon atoms substituted by halogen atoms or benzylamino groups; And oximes having at least one of an aromatic hydrocarbon group and a cyclic or straight-chain aliphatic hydrocarbon group having 2 to 8 carbon atoms.

Specific examples of aliphatic alcohols having cyclic, branched hydrocarbon groups having 4 to 16 carbon atoms include cyclohexanol, 4-methylcyclohexanol, n-hexadecyl alcohol, n-hexyl alcohol, 2-ethylhexanol, 3-hexanol , Tertiary butyl alcohol and tertiary amyl alcohol. Specific examples of substituted aliphatic alcohols having 2 to 8 carbon atoms are benzyl alcohol, 2- (benzylamino) ethanol and 2,2,2-trichloroethanol. Particular examples of diols of polyhydric alcohols are 1,6-hexanediol and 2,5-secacid diols. Specific examples of phenols are cresols and xylenols. Specific examples of oximes are benzal doxime, cyclohexyl aldoxime and n-hexyl aldoxime. These hydroxyl containing organic compounds can be used individually or in the form of combinations of two or more thereof.

The amount of component (C) in the composition is in the range of 0.5 to 50 parts by weight, preferably 1 to 35 parts by weight, per 100 parts by weight of component (A). If the amount thereof is less than 0.5 part by weight, no adhesive effect is produced. If the amount exceeds 50 parts by weight, the composition may be curable or the cured rubbery product may be degraded in mechanical properties.

Although some of the compositions according to the invention undergo a curing reaction at ambient temperature without the aid of a catalyst, depending on the type of component (B), most compositions add a curing catalyst as component (D) to promote crosslinking. It is desirable to. Examples of suitable curing catalysts include amine compounds such as dimethylhexylamine, diethylhydroxylamine, tetramethylguanidine and tetramethylguanidinopropyltriketoxysilane, quaternary ammonium salts such as tetramethylammonium chloride and trimethyl Hexylammonium chloride); Organic acid metal salts such as zinc octanoate and tin octanoate, organic tin compounds such as dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dioctyltin dilaurate and Dibutyltin dimaleate) and titanium compounds such as tetrabutyl titanate and 1,3-dioxypropanetitanium cis (ethylacetoacetate). The amount of component (D) used is not particularly limited. For example, dibutyltin dilaurate is typically added in an amount of 0.05 to 1 weight per 100 parts by weight of component (A).

In addition to the essential components (A) to (C) and optional components (D), the compositions according to the invention usually contain an inorganic filler for the purpose of imparting mechanical strength or hardness to the cured rubbery product. Inorganic fillers known in the art can be used, such as fumed silica, precipitated silica, silica aerogels, ground silica, diatomaceous earth and calcium carbonate. These inorganic fillers can be used individually or in combination. These may be used by themselves or may be used by surface treatment with an organosilicon compound such as polydimethylsiloxane, octamethylcyclotetrasiloxane or hexamethyldisilazane.

Although varying with the type of filler or the end use of the composition, the filler is typically added in amounts up to 150 parts by weight per 100 parts by weight of component (A). If the amount of filler exceeds 150 parts by weight, the composition is not easy to handle before curing, and the resulting cured product does not have sufficient mechanical properties.

If desired, the composition may further contain adhesion promoters or other modifiers.

The composition of the present invention may be prepared by mixing components (A) to (C) and, optionally, optional components (eg, inorganic fillers, catalysts and other additives) under anhydrous atmosphere.

The composition containing component (C) may be applied directly to an untreated polyolefin resin (such as polypropylene or polyethylene) and then cured to provide a curing product with good adhesion.

Thus, the composition acts as an adhesive or sealing compound for polyolefin substrates, thereby facilitating bonding of polyolefin substrates that were previously impossible or difficult to handle. Therefore, despite the possibility of mass production, it is expected that the practicality of polyolefin resin, which has been limited because of poor adhesion, will be extended over a wide range.

The invention will be described in more detail with reference to the following examples, but the invention should not be considered as being limited thereto. All parts are parts by weight unless otherwise noted.

Example 1

100 parts of dimethyl polysiloxane having a viscosity of 10,000 cSt at 25 ° C. and end portions of silanol groups and 14 parts of fumed silica (specific surface area: about 200 m 2 / g) surface-treated with dimethyldichlorosilane are homogeneously kneaded . Under anhydrous atmosphere, 9 parts of vinyltris (butanone oxime) silane, 0.2 parts of dibutyltin dimaleate and 15 parts of cyclohexanol were added thereto, followed by kneading to obtain a room temperature-curable organopolysiloxane composition.

A pair of polypropylene or polyethylene films of length 8 cm, width 2.5 cm and thickness 0.2 cm, shown in Table 1 below, was combined with the composition obtained above to prepare a test piece as shown in FIG. After 7 days of aging at 20 ° C. and 55% RH, a shear adhesion test at a tensile rate of 50 mm / min was performed on the specimens to determine the shear bond strength (LSS) and the percent cohesive failure (CF). To obtain. The results obtained are shown in Table 1 below.

[Example 2 and Comparative Examples 1 and 2]

Replacing cyclohexanol as component (C) with 1-hexanol (Example 2), excluding cyclohexanol (Comparative Example 1), or replacing cyclohexanol with a compound that does not contain hydroxyl groups A room temperature curable organopolysiloxane composition was prepared in the same manner as in Example 1 except that (Comparative Example 2). Test pieces are prepared using these compositions and tested in the same manner as in Example 1. The results obtained are shown in Table 1 below.

TABLE 1

Note: ^* : Product of Noblen MH8 (Mitsubishi Petrochemical Co., Ltd.)

^** : Hizex 5000 (product of Mitsui Petrochemical Industries. Ltd.)

Example 3

100 parts of dimethyl polysiloxane having both ends terminated with silanol groups and having a viscosity of 40,000 cSt at 25 ° C. and 24 parts of fumed silica (specific surface area: about 200 m 2 / g) surface-treated with polydimethylsiloxane are homogeneously kneaded. Under anhydrous atmosphere, 8.5 parts of methyltrisisopropeneoxysilane, 0.5 parts of tetraketylguanidinopropyltrimethoxysilane, and 25 parts of 2,2,2-trichloroethanol were added thereto, followed by kneading to obtain room temperature-curable organopolysiloxane. Obtain the composition.

Test pieces are prepared using the resulting composition, aged, and tested in the same manner as in Example 1. The results obtained are shown in Table 2 below.

TABLE 2

Note: ^* : Noble MH8 (Mitsumi City Petrochemical Company, Limited)

^** : Hizex 5000 (Mitsui Petrochemical Industries, Limited)

Example 4

Homogenized both ends are terminated with methyldimethoxysilyl groups, 100 parts of dimethylpolysiloxane having a viscosity of 20,000 cSt at 25 ° C. and 16 parts of fumed silica (specific surface area: about 180 m 2 / g) surface-treated with hexamethyldisilazane Knead it. Under anhydrous atmosphere, 4.5 parts of phenyltriethoxysilane, 0.1 part of dibutyltin dilaurate and 10 parts of benzaldoxim were added thereto, followed by kneading to obtain a room temperature curable organopolysiloxane composition.

Test pieces are prepared using the resulting composition, aged, and tested in the same manner as in Example 1. The results obtained are shown in Table 3 below.

TABLE 3

Note: ^* 1: Mitsumi Petrochemical Co., Ltd., Limited.

^* 2: Product of Shin Kobe Electric Machinery Co., Ltd. (Shin Kobe Electric Machinery Co., Ltd.).

^* 3: Mitsui Petrochemical Industries, Limited.

^* 4: Shin Gope Electric Machinery Co., Ltd.

^* 5: Showa Denko KK.

While the invention has been described in more detail with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (10)

(A) 100 parts by weight of organopully siloxane terminated with silanol group or alkoxy group, (B) alkoxy group, enoxy group, isocyanate group, oxime group, organoamino group or amide bonded to silicon atom per molecule A room temperature-curable organopolysiloxane composition comprising 0.1 to 30 parts by weight of an organosilicon compound comprising two or more groups, and 0.5 to 50 parts by weight of a (C) hydroxyl-containing organic compound capable of swelling a polyolefin resin. The room temperature curable organopolysiloxane composition according to claim 1, further comprising an essential amount of a curing catalyst (D). The room temperature-curable organopolysiloxane composition according to claim 1, wherein the organopolysiloxane has a viscosity of 100 to 500,000 cSt at 25 ° C. The room temperature-curable organopolysiloxane composition according to claim 1, wherein the organopolysiloxane has a viscosity of 2,000 to 100,000 cSt at 25 ° C. The room temperature-curable organo pulleysiloxane composition of claim 1, wherein the alkoxy group is methoxy, ethoxy or isopropoxy. The room temperature-curable organopolyacid composition according to claim 1, wherein the amount of the organosilicon compound (B) is 0.5 to 15 parts by weight per 100 parts by weight of component (A). The room temperature-curable organopolysiloxane composition according to claim 1, wherein the amount of hydroxyl-containing organic compound (C) is 1 to 35 parts by weight per 100 parts by weight of component (A). The compound of claim 1, wherein the hydroxyl containing organic compound comprises an aliphatic alcohol having a cyclic, straight or branched hydrocarbon group of 4 to 16 carbon atoms; Aliphatic alcohols having 2 to 8 carbon atoms substituted by aromatic hydrocarbon groups, halogen atoms or benzylamino groups; Aliphatic diols having 6 to 18 carbon atoms; phenol; And an oxime having at least one of an aromatic hydrocarbon group and a cyclic, straight or branched chain aliphatic hydrocarbon group having 2 to 8 carbon atoms. The compound of claim 1, wherein the hydroxyl containing organic compound comprises an aliphatic alcohol having a cyclic or straight chain hydrocarbon group having 4 to 16 carbon atoms; Aliphatic alcohols having 2 to 8 carbon atoms substituted by halogen atoms or benzyl amino groups; And an oxime having at least one of an aromatic hydrocarbon group and a cyclic or straight chain aliphatic hydrocarbon group having 2 to 8 carbon atoms. The compound of claim 1, wherein the hydroxyl containing organic compound comprises an aliphatic alcohol having a cyclic hydrocarbon group having 4 to 16 carbon atoms; Aliphatic alcohols having 2 to 8 carbon atoms substituted by halogen atom benzylamino groups; And an oxime having at least one of an aromatic hydrocarbon group and a cyclic or straight-chain aliphatic hydrocarbon group having 2 to 8 carbon atoms.